Abstract:

Despite several decades of study, several fundamental questions about Bantu linguistic relationships remain unresolved, as well as numerous questions of detail. Phylogenetic analysis has shown that Bantu languages fit a branching-tree model
of evolution surprisingly well, but a tree model does not explain all the variation in the Bantu linguistic data. Moreover, several different Bantu trees appear
to fit the data almost equally well. Our difficulties in resolving the Bantu tree are often ascribed to a lack of data and research, and it is true that there are many more Bantu languages than linguists. However there are probably also more fundamental reasons why a single Bantu tree has proven elusive, arising from
the historical processes under which these languages developed. In this chapter, we show how the networkbuilding method Neighbor-Net (Bryant & Moulton 2003) can be used to distinguish between different historical reasons why some linguistic relationships are not well resolved. We test three hypotheses for why some Bantu languages might not fit a tree model well: rapid radiation, linguistic borrowing and dialect chains, all thought to have been widespread within the Bantu family.